Urinary incontinence, which is a condition involving involuntary loss of urine, is a problem with millions of people. It is much more prevalent among women than men. In some patients, loss of urine is associated with transient increases in intra-abdominal pressure that result from activities such as coughing, sneezing, lifting, straining, exercise and in severe cases, even simply changing body position. This is called stress incontinence.
The normal urinary continence mechanism combines contributions from several components including muscles in and around the urethra, blood pressure in the urethral vascular plexus between the smooth muscle in the urethral wall and the epithelial lining, the mucosal seal between the walls of the closed urethral lumen (coaptation), and support from endopelvic fascia. During urination the muscles in and around the urethra relax and the bladder muscle (the detrusor) contracts. Fluid pressure from the bladder overcomes the mucosal seal, the lumen opens and urine is expelled.
While the bladder is filling, increases in bladder pressure normally induce reflex reactions in the muscles of the continence system to increase urethral closure pressure. This reflex response is normally adequate to prevent involuntary urine loss. If the resistance to urethral opening is insufficient to keep the lumen sealed, the female patient experiences episodes of stress incontinence. Stress incontinence results from inadequate functioning of one or more of the components of the normal continence system.
Options currently available for management of female urinary stress incontinence include the use of externally applied absorbent products, pelvic muscle exercises, electrical stimulation of pelvic muscles, devices that occlude the urethra either internally or externally at the urethral meatus, and injections that add bulk to the urethral wall and surgery. A number of external and internal female continence devices have been patented.
U.S. Pat. No. 5,074,855 discloses a device for controlling urinary incontinence in a human female including a resilient pad configured to seal against and occlude the urethral meatus of the user. A similar device is disclosed in U.S. Pat. No. 5,336,208. In those devices, an adhesive is provided to seal the body of the device against the urethral meatus.
International Applications No. 96/39989, 96/39990 and 96/39991 each disclose a female urinary incontinence device in the form of an urethral cap with a partially deformable body portion, a hand gripping portion and a body contacting surface. The body portion defines a chamber which allows for a vacuum seal when applied to the patient""s body.
U.S. Pat. No. 5,082,006 has a shaft to be inserted into the urethra and one or more knobs on the shaft to plug the passage of urine therethrough. A flap on the proximal end of the shaft holds the positioning of the shaft in the urethra.
Each of the above devices prevents urinary loss by occluding the internal or external urethral orifice and each has to be removed by the patient to allow micturition.
It is desirable to have a device which satisfactorily prevents urinary loss and also permits voluntary voiding without needing to remove the device from the body of the patient. It has now been found that these benefits may be achieved with a female continence augmentor that prevents involuntary urine loss while allowing urine flow during voluntary micturition. The female continence augmentor, described herein, achieves the desired effects by gently stretching and reshaping the midurethra from within its lumen, Stretching the perimeter of the lumen increases tension in the surrounding midurethral wall bringing the opposing surfaces of the epithelial lining into more intimate contact for enhancing coaptation. Coupled with the action of the regular continence mechanism, the increased tension and improved coaptation make the urethra more resistant to dilation by urine during transient increases in abdominal pressure, thus relieving stress incontinence.
When the user of the female continence augmentor wishes to void, the muscles of her continence mechanism relax, reducing tension in the urethral wall sufficiently to permit dilation of the lumen under normal bladder pressure. The female continence augmentor acts as a spring, exerting force directly proportional to the compressive force applied by the muscles of the continence mechanism. When the continence mechanism relaxes, the force from the augmentor drops to a level that does not significantly increase the fluid pressure required to dilate the urethra for urination. The female continence augmentor maintains contact with the dorsal midurethral wall at all times, but the reduced muscular tension allows urine pressure to stretch the urethra, opening a slit-shaped passage for urine between the ventral urethral wall and the ventral surface of the augmentor.
When voiding is complete, contraction of the sphincteric muscles restores tension in the urethral wall and the female continence augmentor resumes functioning automatically. Thus, the female continence augmentor functions through dynamic interactions with the biological continence mechanism. Its mode of action is clearly different than that of previous intraurethral continence devices, which act as plugs that must be removed or plugs with valves that must be externally activated for voiding.
The female continence augmentor adapted to prevent involuntary urine loss due to transient increases in bladder pressure but to passively allow urine flow during voluntary emptying of the bladder. The female continence augmentor improves urethral coaptation and increases mid-urethral resistance to opening the lumen while the bladder is filling. The female continence augmentor preferably has a mount formed of a resilient material. The mount most preferably adheres to the female body about the urethral exit to support the female continence augmentor in position to prevent inadvertent urine loss through the midurethral lumen. The mount may perhaps include a layer of adhesive applied thereto and the adhesive might be adapted to releasably attach to the female body.
An intralumenal part may be carried on the mount. The intralumenal part preferably includes a resilient portion carried on the mount. The resilient portion can extend into the urethra and could be adapted to at least urge the dorsal midurethral wall in a dorsal direction to stretch and/or reshape the midurethral lumen to have a more arcuate shape transversely thereacross. Thus the midurethral lumen in cross section would preferably exhibit a crescent shape of smaller radius. The intralumenal part might include two struts or a member attached to one or two struts extending from the resilient portion for stretching, reshaping and repositioning the midurethral lumen intralumenally.
The member might be adapted for engaging the urethral wall, especially the midurethral wall to remove laxity therein and for enhancing coaptation and increasing urethral resistance to opening. The patient may void voluntarily with normal muscle control but otherwise without requiring conscious action to operate the female continence augmentor or needing to remove, activate, inactivate, or alter it. Following voiding, the continence augmentation function resumes automatically by removing laxity in the midurethral lumen.
The member could include a coaptation improver located thereon and in position for and adapted for engagement with the adjacent midurethral walls. It is preferred that the coaptation improver be biocompatible hydrophilic material adapted to coat with mucus and mucosa within the urethra to prevent involuntary urine loss. The member may be or include a flexible membrane of polymeric material. The flexible membrane might have a structural shape of opposed major surfaces with interstices thereacross. The opposed major surfaces are preferably surrounded by an edge and are preferably generally rectangular.
The member is supported by one or two struts which extend from the resilient portion to the member to urge it against the wall of the midurethral lumen. The two struts may preferably spread apart relative to each other so that the two struts are closer to one another at the resilient portion than at the sides of the member.
The member or flexible membrane might be coated across at least its opposed major surfaces with the biocompatible hydrophilic material that cooperatively fills any gaps between the midurethral walls and the member or flexible membrane. The biocompatible hydrophilic material may promote adherence therewithin and therebetween to seal and prevent involuntary urine loss thereacross. The member or flexible membrane is preferably bowed along the edge transverse to its sides for forming a resilient structure bearing against the midurethral walls. The flexible membrane may be formed of a mesh preferably of flexible polymer. The flexible membrane could possibly have an arcuate shape between opposite sides thereof wherein the opposed major surfaces might perhaps be concave and convex generally in accord with the contour of midurethral lumen cross section.
A method of making the female continence augmentor preferably may improve urethral coaptation and increase mid-urethral resistance to opening the lumen. The method of making preferably has the steps of forming the mount of resilient material and perhaps including the intra lumenal part carried on the mount for extending into the urethra and adapted to at least urge the dorsal midurethral wall in a dorsal direction to stretch and/or reshape the midurethral lumen to have a more arcuate shape transversely thereacross to exhibit a smaller radius. The intralumenal part might include a member attached to the resilient portion for stretching, reshaping and repositioning the midurethral lumen intralumenally for at least urging the dorsal midurethral wall in a dorsal direction for stretching and/or reshaping the midurethral lumen to be a more arcuate shape transversely thereacross. The method of making may have the steps of connecting the intralumenal part to the mount and locating one or more struts on the resilient portion in position for placement relative to the mount intralumenally. The method of making could include the step of forming by molding the mount of a polymer material. The method of making might have the step of locating the member on one or more struts connected to the resilient portion. Substituting the flexible membrane between two struts may be a step. The method of making preferably has the steps of adding adhesive to the mount and having biocompatible hydrophilic material on the member or the flexible membrane to increase coaptation.
A method of using the female continence augmentor might have the mount connected to an intralumenal part. The method of using preferably may include the steps of inserting the intralumenal part into the urethra so that the struts or member thereon are within the midurethral lumen. The step of placing the mount adjacent to the urethral exit to retain the struts or the member in the midurethral lumen can be performed. Stretching and/or reshaping the inside of the urethra with the struts or member urged by the resilient portion that is preferably connected between the mount and struts might be a step. The method of using may include steps of urging the dorsal midurethral wall in a dorsal direction for stretching and/or reshaping the midurethral lumen to have a more arcuate shape transversely thereacross and engaging the urethral wall, especially the midurethral wall to remove laxity therein and for enhancing coaptation and increasing urethral resistance to opening. The patient may void voluntarily without requiring conscious action to operate the female continence augmentor. That is, there is no need to remove, activate, inactivate or alter it. Following voiding, the female continence augmentor resumes functioning automatically.